Kitchen sink



FIG. 1 is a top plan view showing our new ornamental design for a kitchen sink;

FIG. 2 is a front view of the sink design of FIG. 1, the rear view being a mirror image thereof; and,

FIG. 3 is a right-side view of the sink design of FIG. 1, the left side view being a mirror image thereof. 

The ornamental design for a kitchen sink, as shown and described. 